578 research outputs found
Local Void vs Dark Energy: Confrontation with WMAP and Type Ia Supernovae
No full textIt is now a known fact that if we happen to be living in the middle of a large underdense region, then we will observe an ``apparent acceleration'', even when any form of dark energy is absent. In this paper, we present a ``Minimal Void'' scenario, i.e. a ``void'' with minimal underdensity contrast (of about -0.4) and radius (~ 200-250 Mpc/h) that can, not only be consistent with the supernovae data, but also with the 3-yr WMAP data. We also discuss consistency of our model with various other measurements such as Big Bang Nucleosynthesis, Baryon Acoustic Oscillations and local measurements of the Hubble parameter. We also point out possible other observable signatures.It is now a known fact that if we happen to be living in the middle of a large underdense region, then we will observe an ``apparent acceleration'', even when any form of dark energy is absent. In this paper, we present a ``Minimal Void'' scenario, i.e. a ``void'' with minimal underdensity contrast (of about -0.4) and radius (~ 200-250 Mpc/h) that can, not only explain the supernovae data, but also be consistent with the 3-yr WMAP data. We also discuss consistency of our model with various other measurements such as Big Bang Nucleosynthesis, Baryon Acoustic Oscillations and local measurements of the Hubble parameter, and also point out possible observable signatures
A CRITICAL REVIEW ON THE MATERIAL ASPECTS OF TRIBOELECTRIC NANOGENERATORS (TENG)
No full textTriboelectric nanogenerators (TENG) take the advantage of coupling effect for harvesting energy in the area of electronics for various self-powered applications. These nanogenerators are capable of converting energy in our surroundings into electrical energy by using the process of electrostatic induction and contact electrification. Triboelectric layers of a TENG are formed basically with the use of various polymers, metals and other inorganic materials like PTFE (Poly tetra fluoro ethylene), PDMS (polydimethyl siloxane), FEP (Fluorinated ethylene propylene) and Kapton. Selection of different materials for the device fabrication is very important since it contribute towards the triboelectric effect and also forms the fundamental structure for the proposed TENG device. In this review article, we emphasis mainly on various triboelectric materials considering factors such as stability, flexibility, power density etc., to improve upon the electrical output of the devices for different applications
Jüri Okas’ ‘specific objects’: diverging discourses in Estonian Art in the 1970s.
No full textPreviously in the University eprints HAIRST pilot service at http://eprints.st-andrews.ac.uk/archive/00000367/Article 3 of 6 in issue devoted to the visual culture of the Scandinavian and Baltic region.This article will look at the early works of Estonian architect and artist Jüri Okas and will try to work between diverging languages and interpretations, reading works by Okas against the background of Anglo-american conceptualism and minimalism of the same period. The first part of the paper will analyse a print by Jüri Okas that paraphrases works by the American artist Donald Judd and will try to show how Okas’ concept of minimalism differed from the Western one and the reasons behind it. The second part of the paper will focus on a conceptual book by Jüri Okas, consisting of a series of photographs of everyday and banal architectural objects, and compare it to Rober Venturi’s book on Complexity and Contradiction in Architecture. Finally, a comparison will be made with works of Robert Smithson in the context of concepts of waste, excess and the remainders of industrial civilisationPostprin
Second order phase transition in thermodynamic geometry and holographic superconductivity in low-energy stringy black holes
No full textSuperconducting and Antiferromagnetic Phases of Space-Time
No full textA correspondence between the SO5 theory of high-TC superconductivity and antiferromagnetism, put forward by Zhang and collaborators, and a theory of gravity arising from symmetry breaking of a SO5 gauge field is presented. A physical correspondence between the order parameters of the unified SC/AF theory and the generators of the gravitational gauge connection is conjectured. A preliminary identification of regions of geometry, in solutions of Einstein’s equations describing charged-rotating black holes embedded in de Sitter space-time, with SC and AF phases is carried out
La poétique du vide chez Vaid et la résistance à la violence communautaire
No full textInternational audienceStarting with two major novels of Krishna Baldev Vaid, a contemporary Hindi novelist, the study aims at evidencing the relation between the form in a non-figurative artistic program and the socio-cultural meanings of the text, in a particular stage of the Indian literary history where the question of realism was hotly discussed (section 1). One of the most abstract novels of the author (Dusra na koi), although often stigmatized as a copy of Beckett, appears indeed to be a modern writing of the philosophical renouncement, by means of such stylistic devices as modalization, comparison and metaphor and other decentring devices, as well as the rich intertext with bhakti and classical aesthetics (section 2). The genesis of this style is then deciphered in the great novel on Partition (Guzra hua zamana) and related to the reflection on communal violence, by analyzing the construction of the fluid identities, poly-belonging, scepticism and irony, and the deconstruction of the absolute Truth.A partir de deux œuvres majeures du romancier contemporain hindi Krishna Baldev Vaid, l'étude vise à mettre en évidence entre les formes d'un art de type non figuratif et les signifiés socio-culturels du texte, dans une phase de l'histoire littéraire indienne marquée par les débats sur la notion de réalisme (section 1). Un des romans les plus abstraits de l'auteur (‘Dusra na koi'), bien que souvent dénoncée comme plagiat du ressassement beckettien, se révèle une écriture moderne du renoncement philosophique, par des procédures stylistiques comme la modalisation, la comparaison, le décentrement généralisé, par le riche intertexte des traditions mystiques médiévales et de l'esthétique classique (section2). La genèse de ce style est ensuite déchiffrée dans le grand roman sur la partition (Guzra hua zamana) et mise en rapport avec la réflexion sur les violences communautaires, par l'analyse de la construction des identités fluides et de la poly-appartenance, du scepticisme et de l'ironie, de la déconstruction de la vérité absolue
La poétique du vide chez Vaid et la résistance à la violence communautaire
No full textInternational audienceStarting with two major novels of Krishna Baldev Vaid, a contemporary Hindi novelist, the study aims at evidencing the relation between the form in a non-figurative artistic program and the socio-cultural meanings of the text, in a particular stage of the Indian literary history where the question of realism was hotly discussed (section 1). One of the most abstract novels of the author (Dusra na koi), although often stigmatized as a copy of Beckett, appears indeed to be a modern writing of the philosophical renouncement, by means of such stylistic devices as modalization, comparison and metaphor and other decentring devices, as well as the rich intertext with bhakti and classical aesthetics (section 2). The genesis of this style is then deciphered in the great novel on Partition (Guzra hua zamana) and related to the reflection on communal violence, by analyzing the construction of the fluid identities, poly-belonging, scepticism and irony, and the deconstruction of the absolute Truth.A partir de deux œuvres majeures du romancier contemporain hindi Krishna Baldev Vaid, l'étude vise à mettre en évidence entre les formes d'un art de type non figuratif et les signifiés socio-culturels du texte, dans une phase de l'histoire littéraire indienne marquée par les débats sur la notion de réalisme (section 1). Un des romans les plus abstraits de l'auteur (‘Dusra na koi'), bien que souvent dénoncée comme plagiat du ressassement beckettien, se révèle une écriture moderne du renoncement philosophique, par des procédures stylistiques comme la modalisation, la comparaison, le décentrement généralisé, par le riche intertexte des traditions mystiques médiévales et de l'esthétique classique (section2). La genèse de ce style est ensuite déchiffrée dans le grand roman sur la partition (Guzra hua zamana) et mise en rapport avec la réflexion sur les violences communautaires, par l'analyse de la construction des identités fluides et de la poly-appartenance, du scepticisme et de l'ironie, de la déconstruction de la vérité absolue
Coherent states and particle scattering in loop quantum gravity
No full textQuantum field theory provides us with the means to calculate scattering amplitudes. In recent years a dramatic new development has lead to great simplification of such calculations. This is based on the discovery of the “amplituhedron” in the context of scattering of massless gauge bosons in Yang–Mills theory. One of the main challenges facing Loop Quantum Gravity is the lack of a clear description of particle scattering processes and a connection to flat space QFT. Here we show a correspondence between the space of kinematic data of the scattering N massless particles and U(N) coherent states in LQG. This correspondence allows us to provide the outlines of a theory of quantum gravity based upon the dynamics of excitations living on the the positive Grassmannian
Multiple compound odontomas in mandible: A rarity
No full textOdontomas are benign odontogenic tumors composed of enamel, dentine, and cementum and pulp tissue. They are usually clinically asymptomatic, but often associated with tooth eruption disturbances. The present study reports an unusual case of eleven odontomas in the left lateral incisor-canine region of lower jaw. A 26 years old female presented to the department of orthodontics and dentofacial orthopedics in H.P. Govt. Dental College and Hospital Shimla for the treatment of misaligned teeth. Clinical examination revealed that the lower left lateral incisor was missing. Patient was advised for radiographs, which revealed a mixed radiopaque lesion associated to impacted lower left canine. The histological report in this case indicated a compound odontoma
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